At present, existing portable fire extinguishing apparatuses are generally divided into pressure-storage dry powder fire extinguishing apparatuses and handheld aerosol fire extinguishing apparatuses, wherein a pressure-storage dry powder fire extinguishing apparatus mainly have the following disadvantages: firstly, the pressure-storage dry powder fire extinguishing apparatus causes serious pollution to the environment and serious damage to materials; secondly, the pressure-storage dry powder fire extinguishing apparatus, which needs to store high pressure gases, is large in volume and heavy in weight; thirdly, the pressure-storage dry powder fire extinguishing apparatus, which is a high pressure container, has potential safety hazards and is more dangerous in a high temperature environment of a fire; fourthly, the pressure-storage dry powder fire extinguishing apparatus, which needs to go through regular surveillance tests and inspections, is high in routine maintenance costs etc. By contrast, a portable aerosol fire extinguishing apparatus has obvious advantages and mainly comprises: a cartridge, a cartridge cover arranged on the cartridge, and a pyrotechnic composition, an ignition head, a coolant and a ceramic chip etc. arranged in the cartridge in turn and coated by a heat insulation material. Normally, after the pyrotechnic composition is ignited by the ignition head, a great deal of aerosol smog will be generated by the cartridge through rapid stratified combustion, and after being cooled by a coolant layer, these high temperature aerosols will be ejected from the cartridge cover of the cartridge to act on a fire source directly, thus extinguishing the fire. However, there are also some disadvantages. A coating defect, a pyrotechnic composition crack or a serious blockage of a gas channel may lead to a sudden rise of the pressure in the cartridge to deflagrate the cartridge. As a result, a high pressure gas will thrust the cartridge cover of the cartridge forwards and will be vented rapidly to cast the cartridge cover of the cartridge and other substances in the cartridge forwards at an extremely high speed, thus causing a very large recoil force. The powerful recoil force drives the cartridge cover to move backwards rapidly, which is easy to cause an injury to an operator. At the same time, after explosion venting, the cartridge cover of the inner cartridge of the extinguishing apparatus will also break away from the cartridge and fly outwards for a relatively long distance, which may cause other accidents. In addition, the cartridge of the extinguishing apparatus is easily loosened in a casing and the problem of fixation of the cartridge is a subject to be solved.